fun main(args:Array<String>){
val numbers=listOf(1,2,3,4,5,6,7,8,6,10)
println(numbers.size)
println(numbers)
val numbers1=setOf(1,2,3,4,5,6,7,8,6,10)
println(numbers1.size)
println(numbers1)
// setof 通过下标获取元素 报错
// println(numbers1.elementAt[0])
println(numbers1.first())
println(numbers1.last())
println(numbers1.contains(6))
}